Four Tenth Roots

Problem

Let ω=cos⁡π5+isin⁡π5\omega = \cos\dfrac{\pi}{5} + \mathrm{i}\sin\dfrac{\pi}{5}. Expand

(x−ω)(x−ω3)(x−ω7)(x−ω9)(x - \omega)(x - \omega^3)(x - \omega^7)(x - \omega^9)

as a polynomial in xx with integer coefficients.

Answer

Solution

Difficulty6/10
Topicscomplex numbers, Roots of Unity Filter, algebra, Polynomials

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